• Title/Summary/Keyword: hydrogenation

Search Result 404, Processing Time 0.021 seconds

Hydriding Kinetics on Mg2NiHx-5wt% CaO Composites (Mg2NiHx-5wt% CaO 복합재료의 수소화 속도)

  • SHIN, HYO-WON;HWANG, JUNE-HYEON;KIM, EUN-A;HONG, TAE-WHAN
    • Journal of Hydrogen and New Energy
    • /
    • v.32 no.3
    • /
    • pp.156-162
    • /
    • 2021
  • Mg hydride has a relatively high hydrogen storage amount of 7.6wt%, and inexpensive due to abundant resources, but has high reaction temperature and long reaction time because of treble oxidation reactivity and upper activation energy. Their range of applications could be further extended if their hydrogenation kinetics and degradation behavior could be improved. Therefore, the effect of CaO has improved the hydrogenation kinetics and slowed down the degradation. This study focused on investigating whether to improve the hydrogenation kinetics by synthesizing Mg2NiHx-5wt% CaO composites. The Mg2NiHx-5wt% CaO composites have been synthesized by hydrogen induced mechanical alloying. The synthesized composites were characterized by performing X-ray diffraction, Scanning Electron Microscopy, Brunauer-Emmett-Teller, Thermogravimetric, and Sivert's type automatic pressure-composition-temperature analysis. Hydriding kinetics were performed using an automatic PCT measurement system and evaluated over the temperature range of 423 K, 523 K, and 623 K. As a result of calculating the hydrogen adsorption amount through the hydrogenation kinetics curve, it was calculated as about 0.42wt%, 0.91wt%, and 1.15wt%, the highest at 623 K and the lowest at 423 K.

Fabrication and Evaluation Hydrogenation Absorbing on Mg2NiHx-10 wt% CaF2 Composites (Mg2NiHx-10wt% CaF2 수소저장합금의 제조와 수소화 흡수평가)

  • YU, JE-SEON;HAN, JUNG-HUM;SIN, HYO-WON;HONG, TAE-WHAN
    • Journal of Hydrogen and New Energy
    • /
    • v.31 no.6
    • /
    • pp.553-557
    • /
    • 2020
  • It is possible that hydrogen could replace coal and petroleum as the predominant energy source in the near future, but several challenges including cost, efficiency, and stability. Mg and Mg alloys are attractive hydrogen storage materials because of their lightweight and high absorption capacity. Their range of applications could be further extended if their hydrogenation properties could be improved. The main emphasis of this study was to investigate their hydrogenation properties for Synthesis of 10wt.% CaF2 in Mg2NiHx systems. The effect of BCR (66:1) and MA time (96 hours) on the hydrogenation properties of the composite was investigated. also, Mg2NiHx-10wt% CaF2 composites prepared by Mechanical Alloying are used in this work to illustrate the effect of catalysts on activation energy and kinetics of Magnesium hydride.

Thickness Dependence of Hydrogenation Characteristics on Pd Films (Pd 박막의 두께 변화에 의한 수소화 특성 변화)

  • Cho, Young-Sin
    • Journal of Hydrogen and New Energy
    • /
    • v.5 no.2
    • /
    • pp.59-63
    • /
    • 1994
  • Thermally evaporated Pd films on substrate were hydrogenated upto 1 bar of hydrogen gas at room temperature. Thickness dependence on hydrogenation on Pd film is examined in the thickness range between $60{\AA}$ and $800{\AA}$. Hydrogenation kinetics of thinner films(thinner than $500{\AA}$) and that of thicker films are different. Thin film(thickness < $200{\AA}$, substrate temp. = RT) showed recrystallization due to hydrogen induced heat. Hydrogen was absorbed by chemisorption process in ${\alpha}$ phase of thinner films, and diffusion process in ${\alpha}'$ phase of thicker films respectively.

  • PDF

A Study on the Thermal Cycling Effect on the Hydrogenation Kinetics of Mg2Cu (Mg2Cu 수소저장합금의 thermal cycling 효과에 관한 연구)

  • Han, Jeong-Seb
    • Journal of Hydrogen and New Energy
    • /
    • v.2 no.1
    • /
    • pp.69-75
    • /
    • 1990
  • The effect of thermal cycling on the hydrogenation characteristics of the $Mg_2Cu-H$ system was investigated in order to study of intrinsic degradation of the system. The hydrogen storage capacity decreased with thermal cycling from $573^{\circ}K$ to $663^{\circ}K$. By the thermal analysis it is found that stable $MgH_2$ hydride is formed during thermal cycling. With a heat treatment at $693^{\circ}K$ at a hydrogen pressure of 16 atm, the hydrogenation rate drastically decreased. From these observation, it suggested that the intrinsic degradation of $Mg_2Cu$ system results from mainly the formation of stable $MgH_2$ hydride phase.

  • PDF

Deformation of the Rolled Plate with Hydrogen Absorption-Desorption Cycling (수소저장-방출싸이클링에 의한 압연판재의 변형)

  • 정영관;김경훈;정선환;김창덕;이근진;박규섭
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2002.05a
    • /
    • pp.861-864
    • /
    • 2002
  • Deformation of the specimen was investigated on hydrogen absorption-desorption cycling. In order to study this problem, the cold rolled palladium thin plate as the specimen had been used. By using the electrochemical method, the palladium plate specimen was cyclically hydrogenated in the 0.1 mol $H_2SO_4$ electrolyte. As results, it is noted that the thickness of the plate specimen gradually increased in increasing hydrogenation cycles whereas the width and the length decreased. Also, grains in the plate specimen were greatly deformed after hydrogenation cycling. But hydrogen absorption rate scarcely changed.

  • PDF

Analysis of Sterols and Its Hydrogenation to Stanols in Vegetable Oils for the Development of a Cholesterol Absorption-lowering Neutraceutical (콜레스테롤 흡수저하 기능성소재 개발을 위한 식물성 유지 중이 Sterols 분석 및 Stanol로의 수소첨가반응)

  • 인만진;김동청;채희정;김명희;임병순;김의용
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.28 no.5
    • /
    • pp.980-983
    • /
    • 1999
  • The contents of sterols and stanols in vegetable oils and mist oil were analyzed by gas chromatography using a capillary column. The total sterol contents showed high values of 0.67~0.89g/100g in corn oil, rice bran oil, red pepper seed oil and sesame oil. Mist oil, a byproduct of soybean oil manufacture, was a suitable raw material for the production of stanol since it showed high sterol content (10.2g/100g). In the hydrogenation of sterol contained in mist oil using Pd catalyst, the effects saponification of oil were examined. The conversion of sterol to stanol was improved by a factor of 4~5 through saponification of oil, compared to the reaction without saponification.

  • PDF

The Effects of Hydrogenation in n-channel Poly-si TFT with LDD Structure (LDD구조를 갖는 n-채널 다결정 실리론 TFT소자에서 수소처리의 영향)

  • 장원수;조상운;정연식;이용재
    • Proceedings of the IEEK Conference
    • /
    • 2003.07b
    • /
    • pp.1105-1108
    • /
    • 2003
  • In this paper, we have fabricated the hydrogenated n-channel polysilicon thin film transistor (TFT) with LDD structure and have analyzed the hot carrier degradation characteristics by electrical stress. We have compared the threshold voltage (Vth), sub-threshold slope (S), and trans-conductance (Gm) for devices with LDD (Lightly Doped Drain) structure and non-LDD at same active sizes. We have analyzed the hot carrier effects by the hydrogenation in devices. As a analyzed results, the threshold voltage, sub-threshold slope for n-channel poly-si TFT were increased, trans-conductance was decreased. The effects of hydrogenation in n-channel poly-si TFT with LDD structure were shown the lower variations of characteristics than devices of the non-LDD structure with nomal process.

  • PDF

Structures of Fraxinellone Derivatives by Hydrogenation with $PtO_2$ in HOAc (백선피의 성분 Fraxinellone의 백금산 촉매에 의한 환원물질의 구조)

  • Kim, Ju Sun;Kang, Sam Sik
    • Korean Journal of Pharmacognosy
    • /
    • v.44 no.1
    • /
    • pp.6-9
    • /
    • 2013
  • Two fraxinellone-based hydrogenated derivatives were prepared from fraxinellone, a well-known degraded limonin, via catalytic hydrogenation in the presence of $PtO_2$ in HOAc. Their structures were confirmed as (3S,3aR,3'R)-3a,7-dimethyl-3-(tetrahydrofuran-3-yl)-3a,4,5,6-tetrahydroisobenzofuran-1(3H)-one and (3S,3aR,2'R)-3-((R)-1-hydroxybutan-2-yl)-3a,7-dimethyl-3a,4,5,6-tetrahydroisobenzofuran-1(3H)-one on the basis of 2D NMR assignments. The $^{13}C$ NMR assignments of two quaternary carbons in the ${\alpha}$,${\beta}$-unsaturated carbonyl moiety of ${\gamma}$-butyrolactone core of fraxinellone should be revised.

Effect of Ball milling on the Hydrogenation Properties of Mg-Ni Powder Mixtures (볼밀링이 마그네슘-니켈 혼합분말의 수소화 반응특성에 미치는 영향)

  • Han, Ji-Seong;Kim, Ki-Won;Ahn, In-Shup;Ahn, Hyo-Jun
    • Journal of Hydrogen and New Energy
    • /
    • v.9 no.2
    • /
    • pp.85-92
    • /
    • 1998
  • The hydrogenation behavior of $Mg_2Ni$ powder prepared by ball milling has been studied. Ball milled $Mg_2Ni$ was transformed to an amorphous-like state after 200hr ballmilling, and crystallized to $Mg_2NiH_x$ by hydrogenation at got. The hydrogen storage capacity gradually increased as a function of ball milling time. $Mg_2Ni$ by 400hr ballmilling shows higher hydrogen storage capacity (3H/M) than $Mg_2Ni$ by VIM(Vacuum Induction Melting).

  • PDF

Determining the Hydrogenation Condition of Oil & Fats by the Orthogonal Table L8(27) (직교표(直交表) L8(27)에 의한 유지(油脂)의 경화반응조건(硬化反應條件)의 결정(決定))

  • Gu, Bon-Cheol;Song, Seo-Il
    • Journal of Korean Society for Quality Management
    • /
    • v.19 no.2
    • /
    • pp.166-171
    • /
    • 1991
  • The purpose of this paper is on determining the optimum hydrogenation conditions of oil & fats of toilet soap for improving the process capability and quality. This paper employs the orthogonal table $L_8(2^7)$ The result of this paper is as follows: (1) The optimum condition of hydrogenation is determined as $A_1$, $B_2$, $C_2$, $D_2$ and the presumed value of average melting point is $42.54{\pm}1.70$(${\alpha}=0.05$) (2) The index of process capability(Cp)is improved from 0.50 to 1.39.

  • PDF